Created attachment 163338 [details] A Valgrind trace of the program execution. SUMMARY Many KDE applications exhibit the following behavior. They do not display a window, nor write anything to the console, but they use 100% of one CPU and their memory consumption increases enormously (1 more GB every 5-10 seconds) until the OS runs out of RAM and freezes. STEPS TO REPRODUCE Run `dolphin` in a terminal, and `htop` in another terminal. (Other applications than dolphin have a similar behaviour). OBSERVED RESULT Nothing is displayed in the terminal and no window appears. The process `dolphin` is reported by `htop` to consume around 100% CPU and to increase its memory consumption by 1 GB every 5-10 seconds, until the process is interrupted or the system runs out of memory. EXPECTED RESULT The applications start a graphical window. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Linux 5.15.138-1-MANJARO #1 SMP PREEMPT (available in About System) KDE Plasma Version: plasmashell 5.27.9 KDE Frameworks Version: 5.112.0-1; dolphin 23.08.3 Qt Version: Qt 5.15.11 ADDITIONAL INFORMATION I encountered this problem with the following applications: Kate, Dolphin, System settings, and starting a Plasma session (since Plasma doesn't work, I use the i3 WM for the other applications). Konsole and KDE Connect work fine; Okular also works fine as long as I don't open the "Open File" or "Print to File" menus. Sometimes, `/usr/lib/kactivitiesmanagerd` starts and exhibits the same behaviour. I suspect this is linked to the kactivities framework, but I'm not sure. I also tried running `dolphin` in `valgrind` (`valgrind --leak-check=yes dolphin 2>&1 | tee dolphin.log`). The log is attached. THINGS I TRIED - reinstalling applications (`pamac reinstall kcoreaddons kconfig5 kactivities5 kactivities-stats5 dolphin kate okular`) - removing `~/.local/share/kactivitiesmanagerd` and `~/.config/KDE*`
- GDB gives the following stack trace: ``` #2 0x00007ffff607c55b in QMimeType::inherits(QString const&) const () at /usr/lib/libQt5Core.so.5 #3 0x00007ffff7422d4c in KBuildSycoca::recreate(bool) () at /usr/lib/libKF5Service.so.5 #4 0x00007ffff740f4ff in KSycocaPrivate::buildSycoca() () at /usr/lib/libKF5Service.so.5 #5 0x00007ffff740f6de in KSycocaPrivate::checkDatabase(QFlags<KSycocaPrivate::BehaviorIfNotFound>) () at /usr/lib/libKF5Service.so.5 #6 0x00007ffff7410963 in KSycoca::ensureCacheValid() () at /usr/lib/libKF5Service.so.5 #7 0x00007ffff73ed7af in KService::serviceByDesktopName(QString const&) () at /usr/lib/libKF5Service.so.5 ``` The function `QMimeType::inherits(QString const&) const ()` runs forever and never returns. - It turns out that one file (`~/.local/share/mime/packages/appimagekit_95f6eff3ef1e2ad046cfd66717eee4da_freedesktop.org.xml`) was responsible for the issue. Deleting or moving the file solves the problem.